The present disclosure relates to a display apparatus having a built-in touch detection function for detecting an external approaching object, a drive circuit, a method of driving such a display apparatus, and electronic devices including the same.
In recent years, display apparatuses, such as a liquid-crystal display apparatus, etc., equipped with a touch detection function for detecting an external approaching object, such as a finger, etc., are attracting people's attention. On such apparatuses, various kinds of button images, etc., are displayed so that a user is allowed to input information using those images in place of ordinary mechanical buttons. It is not necessary for the user of the display apparatuses with such a touch detection function to use an input device, such as a keyboard, a mouse, or a keypad. Accordingly, use of such display apparatuses is on the rise in mobile information terminals, such as cellular phones, etc., in addition to computers.
There are several touch detection methods. A capacitive type is provided as one of the methods. For example, Japanese Unexamined Patent Application Publication No. 2009-258182 has proposed a display apparatus in which a common electrode for display that is originally disposed in the display apparatus is used as one of a pair of touch-sensor electrodes, and the other of the electrodes (touch detection electrodes) is disposed so as to intersect the common electrode. A capacitance is formed between the common electrode and the touch detection electrode, and the capacitance changes in accordance with an external approaching object. Using the change, the display apparatus analyzes a touch detection signal that appears on the touch detection electrode when applying a touch-detection drive signal to the common electrode so as to detect the external approaching object. In the display apparatus, a drive signal is applied to the common electrodes in sequence to perform progressive scan in order to carry out display operation. Also, a touch detection signal that appears on the touch detection electrode in accordance with the drive signal is analyzed so that touch detection operation is performed.